Nuclear and Mitochondrial SSU rRNA Genes Reveal Hidden Diversity of Endosymbionts in Freshwater Planarians and Challenge Their Traditional Classification in Astomatia.

Like many other aquatic animals, freshwater planarians have also become partners of symbiotic ciliates from the class Oligohymenophorea. In the present study, we explored the hidden diversity and addressed the questionable systematic position of mouthless obligatory gut endosymbionts of freshwater planarians, using the nuclear and mitochondrial SSU rRNA genes. Although all isolated ciliates morphologically corresponded to a single species, molecular analyses suggested the existence of three genetically distinct entities: , nov.

Multi-Gene Phylogeny of the Ciliate Genus (Ciliophora, Hypotrichia), With Integrative Description of Two Species, Spec. nov. and (Cohn, 1866).

Many hypotrich genera, including , are taxonomically challenging and in a need of integrative revision. Using morphological data, molecular phylogenetic analyses, and internal transcribed spacer 2 (ITS2) secondary structures, we attempt to cast more light on species relationships within the genus . The present multifaceted approach reveals that (1) a large-sized species with numerous macronuclear nodules, isolated from sandy littoral sediments in southern China, is new to science and is endowed here with a name, spec.

Multiple independent losses of cell mouth in phylogenetically distant endosymbiotic lineages of oligohymenophorean ciliates: A lesson from Clausilocola.

The cell mouth is a property of the vast majority of free-living and endosymbiotic/epibiotic ciliates of the class Oligohymenophorea. Cytostome, however, naturally absents in the whole endosymbiotic subclass Astomatia and was naturally or experimentally lost in a few members of the subclass Hymenostomatia. This poses a question of how homoplastic might be the lack of oral structures in the oligohymenophorean evolution.

Diversity and Eco-Evolutionary Associations of Endosymbiotic Astome Ciliates With Their Lumbricid Earthworm Hosts.

Coevolution of endosymbionts with their hosts plays an important role in the processes of speciation and is among the most fascinating topics in evolutionary biology. Astome ciliates represent an interesting model for coevolutionary studies because they are so tightly associated with their host organisms that they completely lost the cell oral apparatus. In the present study, we used five nuclear markers (18S rRNA gene, ITS1-5.

Cryptic host-driven speciation of mobilid ciliates epibiotic on freshwater planarians.

Mobilids are among the most taxonomically diverse but morphologically uniform groups of epibiotic ciliates. They attach to their hosts by means of an adhesive disc as harmless commensals such as Urceolaria, or as parasites causing significant economic loss such as some Trichodina species. We investigated the diversity, species boundaries, and phylogenetic relationships of mobilids associated with freshwater planarians, using 114 new sequences of two mitochondrial (16S rRNA gene and cytochrome c oxidase gene) and five nuclear (18S rRNA gene, ITS1-5.

Silicon Uptake and Localisation in Date Palm () - A Unique Association With Sclerenchyma.

Date palm () can accumulate as much as 1% silicon (Si), but not much is known about the mechanisms inherent to this process. Here, we investigated in detail the uptake, accumulation and distribution of Si in date palms, and the phylogeny of Si transporter genes in plants. We characterized the PdNIP2 transporter following heterologous expression in oocytes and used qPCR to determine the relative expression of Si transporter genes.

Reconciling morphological and molecular classification of predatory ciliates: Evolutionary taxonomy of dileptids (Ciliophora, Litostomatea, Rhynchostomatia).

The order Dileptida is a small group of predatory ciliates characterized by a proboscis serving for prey capture. Although monophyly of the order is strongly supported, generic relationships between dileptid taxa were left mostly unresolved in 18S rRNA gene phylogenies. To overcome this problem, we applied the synergistic effect of combining multiple molecular markers with morphological data.

Phylogenetic relationships of the ciliate class Heterotrichea (Protista, Ciliophora, Postciliodesmatophora) inferred from multiple molecular markers and multifaceted analysis strategy.

The ciliate class Heterotrichea is defined by somatic dikinetids bearing postciliodesmata, by an oral apparatus consisting of a paroral membrane and an adoral zone of membranelles, as well as by features of nuclear division involving extramacronuclear microtubules. Although phylogenetic interrelationships among heterotrichs have been analyzed several times, deeper nodes of the heterotrichean tree of life remain poorly resolved. To cast more light on the evolutionary history of heterotricheans, we performed phylogenetic analyses of multiple loci (18S rRNA gene, ITS1-5.

Prevalence of partnerships between bacteria and ciliates in oxygen-depleted marine water columns.

Symbioses between Bacteria, Archaea, and Eukarya in deep-sea marine environments represent a means for eukaryotes to exploit otherwise inhospitable habitats. Such symbioses are abundant in many low-oxygen benthic marine environments, where the majority of microbial eukaryotes contain prokaryotic symbionts. Here, we present evidence suggesting that in certain oxygen-depleted marine water-column habitats, the majority of microbial eukaryotes are also associated with prokaryotic cells.

Genealogical analyses of multiple loci of litostomatean ciliates (Protista, Ciliophora, Litostomatea).

The class Litostomatea is a highly diverse ciliate taxon comprising hundreds of free-living and endocommensal species. However, their traditional morphology-based classification conflicts with 18S rRNA gene phylogenies indicating (1) a deep bifurcation of the Litostomatea into Rhynchostomatia and Haptoria+Trichostomatia, and (2) body polarization and simplification of the oral apparatus as main evolutionary trends in the Litostomatea. To test whether 18S rRNA molecules provide a suitable proxy for litostomatean evolutionary history, we used eighteen new ITS1-5.

Class Cariacotrichea, a novel ciliate taxon from the anoxic Cariaco Basin, Venezuela.

The majority of environmental micro-organisms identified with the rRNA approach have never been visualized. Thus, their reliable classification and taxonomic assignment is often difficult or even impossible. In our preliminary 18S rRNA gene sequencing work from the world's largest anoxic marine environment, the Cariaco Basin (Caribbean Sea, Venezuela), we detected a ciliate clade, designated previously as CAR_H [Stoeck, S.

Phylogeny and classification of the Litostomatea (Protista, Ciliophora), with emphasis on free-living taxa and the 18S rRNA gene.

The class Litostomatea is a highly diverse ciliate taxon comprising hundreds of species ranging from aerobic, free-living predators to anaerobic endocommensals. This is traditionally reflected by classifying the Litostomatea into the subclasses Haptoria and Trichostomatia. The morphological classifications of the Haptoria conflict with the molecular phylogenies, which indicate polyphyly and numerous homoplasies.

Morphological and taxonomical studies on two soil haptorid ciliates (Ciliophora, Litostomatea): Clavoplites haranti sp. n. and Enchelys terrenum (Foissner, 1984) comb. n., and taxonomy of the family Enchelyidae Ehrenberg, 1838.

The morphology and infraciliature of two soil haptorid ciliates, Clavoplites haranti sp. n. and Enchelys terrenum (Foissner, 1984) comb.

Spathidium seppelti foissneri nov. subspec., Spathidium simplinucleatum nov. stat., and Dileptus americanus Kahl, 1931, one new and two poorly known soil gymnostome ciliates from soils of Slovakia.

The morphology and infraciliature of three soil gymnostome ciliates, Spathidium seppelti foissneri nov. subspec., Spathidium simplinucleatum nov.

A new soil hypotrich ciliate (Protozoa, Ciliophora) from Slovakia: Gonostomum albicarpathicum nov. spec.

The morphology and infraciliature of the soil hypotrich ciliate, Gonostomum albicarpathicum nov. spec., collected from Biele Karpaty (White Carpathian Mts.